VEHICLE APPROACH NOTIFICATION UNIT
A vehicle approach notification unit is mounted to a sound tube of an electromagnetic warning device producing a warning sound, and includes a dynamic speaker that produces a notification sound notifying a presence of a vehicle. The dynamic speaker is mounted to the sound tube and outputs the notification sound through the sound tube to outside of the vehicle. The sound tube has a warning sound outlet at an end of the sound tube and a through hole at a position different from the warning sound outlet.
Latest HAMANAKODENSO CO., LTD. Patents:
This application is based on Japanese Patent Application No. 2012-86808 filed on Apr. 5, 2012, the disclosure of which is incorporated herein by reference in its entirety.
TECHNICAL FIELDThe present disclosure relates to a vehicle approach notification unit.
BACKGROUNDConventionally, a vehicle approach notification unit notifies people of an approaching vehicle with notification sound, and JP-10-201001A discloses such a vehicle approach notification unit having a dynamic speaker which directly produces sound with audible frequencies.
In conventional technologies, a vehicle approach notification unit has a dynamic speaker to make an approaching vehicle audible, and the dynamic speaker is required in addition to a vehicle horn producing warning sound, so an extra space is needed.
Notification sound notifying a presence of a vehicle is required not to be too loud, unlike warning sound, and artificial engine sound, chords, voice sound, and music are preferable as the notification sound. If the notification sound includes low frequencies under 600 Hz, the notification sound becomes quieter, but large dynamic speaker such as woofer is required to produce such low frequencies sound. So, large space and extra cost are needed.
In Japanese Patent Application No. 2011-238815 (U.S. patent application Ser. No. 13/662,913), a dynamic speaker is mounted to a sound tube of an electromagnetic warning device to produce warning sound in a vehicle, and emits notification sound out of the vehicle via the sound tube.
However, a directivity (audible range) of the notification sound is determined by a warning sound outlet such as an exit part of the sound tube which is defined at an end of the sound tube. Thus, when the sound tube mounts the dynamic speaker, it is difficult to control the directivity of the notification sound. In other words, the audible range of the notification sound is difficult to control and extend.
SUMMARYAccording to a first aspect of the present disclosure, a vehicle approach notification unit is mounted to a sound tube of an electromagnetic warning device producing a warning sound, and includes a dynamic speaker that produces a notification sound notifying a presence of a vehicle. The dynamic speaker is mounted to the sound tube and outputs the notification sound through the sound tube to outside of the vehicle. The sound tube has a warning sound outlet at an end of the sound tube and a through hole at a position different from the warning sound outlet.
According to a second aspect of the present disclosure, a vehicle approach notification unit is mounted to a sound tube of an electromagnetic warning device producing a warning sound, and includes a dynamic speaker that produces a notification sound notifying a presence of a vehicle. The vehicle has two of the electromagnetic warning devices, and the dynamic speaker is mounted to each of the two of the electromagnetic warning devices. The dynamic speaker outputs the notification sound having the same frequency from each of the two of the electromagnetic warning devices.
The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:
Embodiments of the present disclosure will be described hereafter referring to drawings. In the embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned with the same reference numeral, and redundant explanation for the part may be omitted. When only a part of a configuration is described in an embodiment, another preceding embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination.
According to a first aspect of the present application, a vehicle approach notification unit has a dynamic speaker 3 producing a notification sound such as artificial engine sound, chord, voice sound or music. The dynamic speaker 3 is mounted to a sound tube 2 of an electromagnetic warning device 1. The sound tube 2 has a through hole β at a position different from a warning sound outlet α, and the notification sound is emitted out of the sound tube 2 through the through hole β.
According to a second aspect of the present disclosure, a vehicle has a first electromagnetic warning device 1A and a second electromagnetic warning device 1B. A vehicle approach notification unit has a dynamic speaker 3 mounted to the first electromagnetic warning device 1A and a dynamic speaker 3 mounted to the second electromagnetic warning device 1B. Both the dynamic speakers 3 output the notification sound having the same frequency.
First EmbodimentA first embodiment will be described with reference to
A vehicle approach notification unit is mounted to a vehicle, and emits a notification sound to notify pedestrians of a presence of the vehicle. The vehicle may be an electric vehicle or a fuel cell vehicle with no engine, a hybrid vehicle in which an engine is stopped in a driving time and a stop time, an idling stop vehicle in which an engine is stopped in a stop time, or an engine vehicle which drives quietly with an engine.
The vehicle has an electromagnetic warning device 1 which generates a warning sound.
The electromagnetic warning device 1 is a vehicle horn producing a warning sound when a horn switch, which is mounted to a steering of the vehicle for example, is operated by an occupant. The electromagnetic warning device 1 is fixed, for example, between a front grille and a heat exchanger used for an air-conditioner such as radiator. The front grille is provided to an air intake port for a wind generated when the vehicle drives.
As shown in
The warning sound generator 4 includes a coil 5, a fixed iron-core 6, a movable iron-core 8, and a current interrupter 9. The coil 5 creates magnetic energy when current is applied. The fixed iron-core 6 may be an attraction core which creates magnetic attracting force when the magnetic energy is produced in the coil 5. The movable iron-core 8 is supported to a center of a diaphragm 7 and movable toward the fixed iron-core 6. The current interrupter 9 continuously intermittently interrupts the energization current in the coil 5 when the coil 5 is supplied with electricity.
The sound tube 2 is constructed by a trumpet portion in which a sound passage is enlarged from a horn inlet to a horn outlet α. Sound generated at the warning sound generator 4 enters the trumpet portion from the horn inlet and comes out of the horn outlet α. Moreover, the sound tube 2 is defined by a spiral horn which is produced by forming the trumpet portion into a spiral shape. The horn outlet a is defined by an open end of the sound tube 2.
The warning sound generator 4 is mounted to a side face of the sound tube 2, and is arranged to generate a warning sound into the horn inlet at the center part of the sound tube 2. The side face of the sound tube 2 is perpendicular to an axis of the spiral shape. For example, the side face of the sound tube 2 is located adjacent to the heat exchanger when the electromagnetic warning device 1 is mounted to the vehicle.
As shown in
The piezoelectric speaker 3 has a vibration system constructed by a piezoelectric element and a diaphragm, and produces an audible frequency sound.
A primary resonance frequency of the vibration system is in the audible range, for example, about 2 kHz.
The piezoelectric element of the piezoelectric speaker 3 is displaced by the expansion or contraction depending on the applied voltage (charge/discharge). The diaphragm is actuated by the displacement of the piezoelectric element, and creates compression wave in the air.
Vehicle information is input from an engine control unit to the control circuit 10. The piezoelectric speaker 3 produces a notification sound when a driving condition is met to notify pedestrians of an approach of the vehicle.
The control circuit 10 includes an actuation determiner 11, a sound generator 12, and an amplifier 13, as shown in
The actuation determiner 11 determines that the driving condition is met and actuates the sound generator 12, for example, when a vehicle speed is under a predetermined value such as 20 km/h. This condition is just for an example, and not limited.
The sound generator 12 includes a notification sound produce program such as an acoustic software, and produces the audible frequency signal producing the notification sound, as an audio electric signal of an audible frequency, using digital technology when the actuation determiner 11 sends a signal to start operating to the sound generator 12.
The amplifier 13 is a power amplifier unit such as Class-B amplifier or Class-D amplifier, and actuates the piezoelectric speaker 3 with the frequency signal producing the notification sound produced by the sound generator 12. The amplifier 13 actuates the piezoelectric speaker 3 to produce the notification sound, as an audible sound, by controlling voltage applied to the piezoelectric speaker 3, in other words, by controlling the charge/discharge state of the piezoelectric element.
The piezoelectric speaker 3 is placed to be opposed to the warning sound generator 4 as shown in
The notification sound produced by the piezoelectric speaker 3 comes out of the vehicle through the sound tube 2. And then, a low frequency sound produced by the piezoelectric speaker 3 is amplified by the sound tube 2, and emitted out.
The warning sound outlet a of the sound tube 2 opens frontward in the vehicle so that the warning sound is emitted frontward from the vehicle.
A line AA in
In the comparison example, the audible range of the notification sound is not controllable when the piezoelectric speaker 3 is mounted to the sound tube 2. Specifically, the directivity of the notification sound is determined by the shape of the warning sound outlet a of the sound tube 2 and the open direction of the warning sound outlet a of the sound tube 2.
In the first embodiment, the sound tube 2 has a through hole 13 at a position different from the warning sound outlet α. For example, the through hole β is located at a middle in the sound passage of the sound tube 2 before the warning sound outlet α.
A notification sound is emitted from not only the warning sound outlet α, but also the through hole β as well, therefore the directivity of the notification sound can be controlled by an acoustic wave emitted from the through hole β. Specifically, the location, the open direction, the number, and the size of the through hole β determine a travel direction and amount of the notification sound.
In the first embodiment, one through hole β is placed at the bottom of the sound tube 2, near the warning sound outlet α as shown in
The through hole β emits notification sound, and the notification sound is reflected on the ground and scattered around the vehicle. In the result, an audible range of the notification sound is made uniform in the radial direction around the vehicle, as shown in a line BB in
According to the first embodiment, the vehicle approach notification unit emits a notification sound produced by the piezoelectric speaker 3 via the sound tube 2. The sound tube 2 has the through hole β aside from the warning sound outlet α, so the audible range of the notification sound can be made controllable.
The location, the number and the size of the through hole β can be easily changed by cut and shave processing. Thus, the directivity of the notification sound can be easily controlled by controlling the number and the size of the through hole β.
The vehicle approach notification unit in the first embodiment has the piezoelectric speaker 3 to produce a notification sound, and also has the sound tube 2 of the electromagnetic warning device 1 as described above. The sound pressure can be raised for a low frequency sound as well as a large-sized dynamic speaker such as a woofer.
Thus, the cost of the vehicle approach notification unit can be reduced, which produces a notification sound including a low frequency sound.
In the first embodiment, the piezoelectric speaker 3 producing an audible sound is used as an example of a small-sized dynamic speaker. The piezoelectric speaker 3 is small in cost, so a cost to produce the vehicle approach notification unit can be reduced.
The piezoelectric speaker 3 is smaller and lighter than a corn speaker, so the piezoelectric speaker 3 can be easily mounted to the electromagnetic warning device 1.
The piezoelectric speaker 3 is placed at a position opposing to the warning sound generator 4. Specifically, the warning sound generator 4 is mounted to a side face of the sound tube 2, and is arranged to generate a warning sound into the horn inlet at the center part of the sound tube 2. The side face of the sound tube 2 is perpendicular to an axis of the spiral shape. For example, the side face of the sound tube 2 is located adjacent to the front grille when the electromagnetic warning device 1 is mounted to the vehicle.
Because the piezoelectric speaker 3 is placed at a position opposing to the warning sound generator 4, the piezoelectric speaker 3 can be easily mounted to the sound tube 2. Moreover, the operation of the warning sound generator 4 is less affected by the piezoelectric speaker 3 which is mounted to the sound tube 2.
Second EmbodimentA second embodiment will be described with reference to
In the second embodiment, the directivity of the notification sound is raised to increase the audible range (distance) of the notification sound ahead of the vehicle, while the audible range of the notification sound is extended uniformly around the vehicle in the first embodiment.
Usually, a vehicle has two electromagnetic warning devices, which are constructed by a first electromagnetic warning device 1A shown in
In the second embodiment, a vehicle approach notification unit includes two dynamic (piezoelectric) speakers 3 mounted to the first electromagnetic warning device 1A and the second electromagnetic warning device 1B, respectively, as shown in
An example of an audible range of a notification sound is shown by an single chain line CC in
When a predetermined condition is satisfied to notify pedestrians of an approaching vehicle, the control circuit 10 applies the same drive signal to the two piezoelectric speakers 3 respectively mounted to the first electromagnetic device 1A and the second electromagnetic device 1B. Each of the piezoelectric speakers 3 produces the notification sound with the same frequency.
Then, the notification sound emitted from the first sound tube 2A and the notification sound emitted from the second sound tube 2B interfere with each other in air, at a front of the vehicle to which the warning sound outlet a is opened. The interference produces a amplitude-synthetic wave in which the sound pressure of the notification sound is enhanced. In the result, as shown by a line EE in
A comparison between the audible range CC or DD of notification sound produced by a single electromagnetic warning device 1A or 1B and the audible range EE of notification sound produced by the first and second electromagnetic warning devices 1A and 1B will be described with
In
As shown in
A third embodiment will be described with reference to
In the third embodiment, the control circuit 10 conducts the energization control for not only the piezoelectric speaker 3 but also the warning sound generator 4. The control circuit 10 applies a signal to the warning sound generator 4 to produce a warning sound having a high sound pressure when an occupant operates a horn switch. Moreover, each of the piezoelectric speaker 3 and the warning sound generator 4 produces a notification sound due to the control conducted by the control circuit 10.
Specifically, the current interrupter 9 intermittently interrupts current flowing in the coil 5 so as to produce a warning sound having a high sound pressure when self-excited voltage, which may be larger than or equal to a threshold value such as 8V, is applied to the warning sound generator 4.
When an occupant of the vehicle operates the horn switch, the control circuit 10 applies self-excited voltage such as battery voltage of 12V to the warning sound generator 4, and the electromagnetic warning device 1 produces a warning sound having a high sound pressure.
On the other hand, the current interrupter 9 does not intermittently interrupt current flowing in the coil 5 when separately-excited voltage, which is lower than the threshold value such as 8V, is applied to the warning sound generator 4. When the coil 5 is actuated by an audio signal with the separately-excited voltage, the diaphragm 7 vibrates in accordance with the audio signal and produces an acoustic wave corresponding to the audio signal. In other words, the warning sound generator 4 works as a dynamic speaker.
As shown in
Thus, the sound pressure of the notification sound produced by both of the piezoelectric speaker 3 and the acoustic generator 4 is enhanced than that produced by the piezoelectric speaker 3 only.
Other EmbodimentIn the above embodiments, one piezoelectric speaker is mounted to the sound tube having the spiral shape. Alternatively, a plurality of the piezoelectric speakers may be mounted to the sound tube to enhance the sound pressure of the notification sound.
In the above embodiments, the piezoelectric speaker is used as an example of a dynamic speaker. Alternatively, other small-sized speaker such as small corn speaker which directly produces audible sound may be applicable.
In the above embodiments, a notification sound is produced by a dynamic speaker such as the piezoelectric speaker. Alternatively, a parametric speaker may be mounted to the vehicle approach notification unit, and both the notification sound produced by the dynamic speaker via the sound tube and the notification sound produced by the parametric speaker may be emitted out of the vehicle.
The dynamic speaker may be actuated when the warning sound generator is actuated, and a tone (frequency) of the warning sound may be controllable by the actuation of the dynamic speaker.
Such changes and modifications are to be understood as being within the scope of the present disclosure as defined by the appended claims.
Claims
1. A vehicle approach notification unit that is mounted to a sound tube of an electromagnetic warning device producing a warning sound, the vehicle approach notification unit comprising:
- a dynamic speaker that produces a notification sound notifying a presence of a vehicle, wherein
- the dynamic speaker is mounted to the sound tube and outputs the notification sound through the sound tube to outside of the vehicle, and
- the sound tube has a warning sound outlet at an end of the sound tube and a through hole at a position different from the warning sound outlet.
2. The vehicle approach warning unit according to claim 1, wherein
- the electromagnetic warning device has a warning sound generator which generates the warning sound, and
- the dynamic speaker is different from the warning sound generator.
3. The vehicle approach warning unit according to claim 1,
- wherein the dynamic speaker is a piezoelectric speaker which outputs an audible frequency sound.
4. The vehicle approach warning unit according to claim 2, wherein
- the sound tube is a spiral-shaped horn, and
- the dynamic speaker is located at a position opposite to the warning sound generator.
5. The vehicle approach warning unit according to claim 1, wherein
- the dynamic speaker is one of two dynamic speakers,
- the vehicle has two electromagnetic warning devices, and the two dynamic speakers are mounted to the two electromagnetic warning devices, respectively, and
- the two dynamic speakers output the notification sound having the same frequency from the two electromagnetic warning devices, respectively.
6. A vehicle approach notification unit that is mounted to a sound tube of an electromagnetic warning device producing a warning sound, the vehicle approach notification unit comprising:
- a dynamic speaker that produces a notification sound notifying a presence of a vehicle, wherein
- the vehicle has two of the electromagnetic warning devices, and the dynamic speaker is mounted to each of the two of the electromagnetic warning devices, and
- the dynamic speaker outputs the notification sound having the same frequency from each of the two of the electromagnetic warning devices.
7. The vehicle approach warning unit according to claim 6, wherein
- the electromagnetic warning device has a warning sound generator which generates the warning sound, and
- the dynamic speaker is different from the warning sound generator.
8. The vehicle approach warning unit according to claim 6,
- wherein the dynamic speaker is a piezoelectric speaker which outputs an audible frequency sound.
9. The vehicle approach warning unit according to claim 7, wherein
- the sound tube is a spiral-shaped horn, and
- the dynamic speaker is located at a position opposite to the warning sound generator.
10. The vehicle approach warning unit according to claim 6,
- each of the two of the dynamic speakers outputs the notification sound through the sound tube to outside of the vehicle, and
- the sound tube has a warning sound outlet at an end of the sound tube and a through hole at a position different from the warning sound outlet.
Type: Application
Filed: Mar 18, 2013
Publication Date: Oct 10, 2013
Applicants: HAMANAKODENSO CO., LTD. (Kosai-city), DENSO CORPORATION (Kariya-city)
Inventors: Toshiaki NAKAYAMA (Miyoshi-city), Koji SUZUKI (Hamamatsu-city)
Application Number: 13/845,719
International Classification: B60Q 5/00 (20060101);